Consult the BOL for more example/sample.
DECLARE @value int
SET @value = 31
-- SELECT CONVERT(decimal(14,2),avg(VoteValue)) ... -- <-- your code
SELECT CONVERT(decimal(14,2),avg(@value))
returns:
34.00
SELECT CONVERT(decimal(14,7),avg(@value))
returns:
34.0000000
Etcetera ...